I - 3x+4
II - x { 11*6 = 66[/tex]
III - [tex] \frac{3x+4+x}{2} \left \
3x+4+x +(3x+4+x )/2 =66
4x+4+2x+2=66
6x+6=66
6x=66-6
6x=60
x=10 , are primul copil
3x+4 = 3*10+4 = 34 are al doilea copil
[tex] \frac{3x+4+x}{2} = \frac{34+10}{2} = \frac{44}{2} =22 [/tex] - are al treilea copil
Verificare : 10+34+22=66